The present invention relates to an apparatus and a method for producing measurement data concerning respiration-related movements of the abdominal wall and/or the thorax of a person. In particular, the present invention relates to a technical teaching the subject of which is the specified detection and monitoring of the respiratory activity of a person.
Breathing in (inspiration) is known to take place through expansion of the thoracic-pulmonary space by the respiratory muscles and through the resulting development of an alveolar partial vacuum in the expanding lung, leading to an inflow of air until pressure is equalized. Breathing out (expiration) takes place predominantly through a passive contraction of the thoracic space by a lowering of the thoracic cage and by an elasticity-related volumetric reduction (retraction) of the lung whereby air flows out as a result of the production of relative alveolar overpressure. Typical disorders of this human breathing process result, for example, from a reduction in lung elasticity or through narrowing of the apertures of the bronchial branches (restrictive or obstructive ventilation disorders), and from possible disorders of the respiratory centre, of diffusion or blood circulation in the lung.
Diaphragmatic respiration is the component of respiration resulting from contraction of the diaphragm (approx. two-thirds of breathing volume).
Attempts to detect and measure a respiration-related expansion of the thoracic and abdominal area during respiration in humans are known from the prior art. Sensors used typically for this purpose operate on piezoelectric principles and generate a comparatively low voltage as the output signal, a force being exerted on such a sensor through the respiration-related expansion of the thoracic or abdominal area during a breathing movement. By suitable processing a respiration signal is generated from a voltage signal produced thereby.
Other systems known from the prior art operate on an impedance principle, i.e. by making use of suitable resistor elements the electrical resistance of which changes through (respiration-related) movements of the thorax or the abdominal wall; in particular strain gauges or suchlike sensors are used for this purpose.
Known approaches of this kind have, however, the disadvantage that only a general detection of human breathing signals is possible, the quality and resolution of the electronic signal obtained normally being insufficient to permit monitoring of further body parameters at acceptable cost and without separate, additional sensors.
In view, in particular, of an inherent biological connection between respiration and cardiac activity it would therefore be desirable to be able to monitor both parameters simultaneously at low cost, and in particular with the use of only one sensor or one sensor arrangement. The same applies to the movement or activity of the person, as could be desirable in particular in the field of the observation of sporting activities.
It is therefore the object of the present invention to provide an apparatus for generating measurement data concerning respiration-related movements of the abdominal wall and/or the thorax of a person which is improved with respect to signal resolution and measurement accuracy in generating a respiration display signal and which therefore also offers, in particular, possibilities of detecting from this respiration display signal further parameters or superposed signals, and creates the possibility of generating with the same sensor system, in addition to data derived from respiratory movement, further data corresponding to other body parameters and functions, including heartbeat.